1. Field of the Invention
The present invention relates to balloon catheters, and more particularly, to miniaturized detachable balloon catheters for use in blood vessels.
2. Description of the Prior Art
It has become a routine practice to use balloon catheters to occlude vessels in certain types of cardiovascular surgery. In this procedure, an inflatable balloon positioned on the distal end of a catheter with a cannula thereon is inserted into a blood vessel and is allowed to move to a proper position by circulation of blood through the vessel. At a desired location, the balloon is inflated by a fluid or by a solidifying filler material until the sides of the balloon are in contact with the walls of the blood vessel. The cannula is then withdrawn from the balloon and the balloon is left in the blood vessel in order to occlude the vessel.
One problem with such prior art detachable balloon catheters is that it is very difficult to precisely control the force required to withdraw the cannula from the balloon. As may be appreciated, if this force is too great, the balloon may be dislodged or repositioned in the blood vessel during detachment of the cannula. If the force required to withdraw the cannula from the balloon is too small, the balloon may become prematurely detached from the cannula during positioning of the balloon within the blood vessel.
Still another problem with such prior balloon catheters is that if a non-solidifying filler material, for example, a radiopaque iso-osmolal solution, is utilized to inflate the balloon, leakage of this material often occurs through the seal at the mouth of the balloon when the cannula is withdrawn from the balloon. Accordingly, an important objective of this invention is to provide a miniaturized detachable balloon catheter which may be used for permanent occlusion of a blood vessel, but one in which the inflatable balloon is not prematurely detached from the cannula.
Heretofore a number of catheter assemblies have been proposed and examples of some of these catheter assemblies are disclosed in the following patents:
U.S. Pat. No. 3,834,399 to Hunter; U.S. Pat. No. 3,919,724 to Sanders et al; U.S. Pat. No. 4,029,875 to Kerber; U.S. Pat. No. 4,085,757 to Pevsner; U.S. Pat. No. 4,282,875 to Serbinenko et al; U.S. Pat. No. 4,341,218 to U; U.S. Pat. No. 4,364,392 to Strother; U.K. Published Patent Application No. 2,019,219; and U.S.S.R. Inventor Certificate 542,523.
The Hunter et al U.S. Pat. No. 3,834,394 discloses a device for effecting occlusion of a blood vessel. The device is inserted into the desired blood vessel, moved to the desired point of occlusion and expanded at that site to a size greater than the diameter of the vessel so as to immovably retain the balloon therein. In one embodiment, the inserting catheter may be unscrewed from the balloon so as to leave the balloon in place.
The Sanders et al U.S. Pat. No. 3,919,724 discloses an implantable breast prosthesis which includes a flexible container having a self-sealing valve or plug. In one embodiment, the prosthesis is used in combination with a balloon catheter having an inflatable cuff.
The Kerber U.S. Pat. No. 4,029,104 discloses a calibrated leak balloon with a plug at the distal end of the balloon having a slit or restricted orifice cut through the plug to permit fluid to leak out of the balloon.
The Pevsner U.S. Pat. No. 4,085,757 discloses a miniature balloon catheter assembly which includes a cannula and an inflatable balloon constructed of a flexible material and detachably mounted on the distal end of the cannula. In one embodiment, the flexible tubing has a plug with a pin hole therein situated within the tubing between a closed distal end of the tubing and an open proximal end of the tubing. A resilient contracting member is received around the tubing and around the plug within the tubing. A hollow needle is mounted to the distal end of the cannula and extends into the flexible tubing with a point of the needle extending through the pin hole so that an open distal end of the needle is in communication with the balloon forming portion of the flexible tubing forward of the plug. The needle has a side opening therein located between the plug and the end of the cannula received in the open end of the flexible tubing. Preferably, an additional wire extends through the needle and terminates in a stop at the end thereof in the form of a sphere which can be drawn against the distal open end of the needle to stop flow of fluid into the balloon forming portion of the flexible tubing whereby further pressure would only be able to exit through the side opening to accomplish detachment by increasing the fluid pressure inside said flexible tubing to expand the proximal end of the tubing to release it from the cannula and to cause the contracting member to expand allowing the needle to be withdrawn after which the contracting member contracts around the tubing and plug to close the pin hole and seal the balloon.
As will be described in greater detail hereinafter, the miniature balloon catheter assembly disclosed in the Pevsner patent does not disclose or suggest a rigid cylinder within which a mouth of a balloon and a sealing valve are mounted, as provided in the balloon catheter assembly of the present invention.
The Serbinenko et al U.S. Pat. No. 4,282,875 discloses a detachable balloon removably attached to the end of a catheter by means of a bulbous portion on the catheter's end. In use, x-ray-TV is used to aid a surgeon in positioning the balloon in the lumen of a pathological vessel of the brain of a patient. By slightly pulling outward, the surgeon detaches the bulb or balloon and withdraws the catheter from the lumen of the vessel.
The U U.S. Pat. No. 4,341,218 discloses a detachable balloon catheter including a dual lumen catheter, one lumen for supplying fluid to a balloon and another lumen for supplying fluid pressure to an expandable balloon forming portion of the catheter adjacent the distal end thereof. A cylinder is mounted to and within the balloon and has a ball therein. An opening to the cylinder is provided and the distal end of the catheter is inserted through the opening into the cylinder and the balloon forming portion thereof is inflated to fix the distal end of the catheter in the cylinder.
After a sufficient amount of fluid is passed through the first lumen into the cylinder and then into the balloon, the pressure in the second lumen is decreased to deflate the balloon forming portion thereof so that the distal end of the catheter can be forced out of the cylinder by the ball which then seals the opening to the cylinder.
The Strother, et al. U.S. Pat. No. 4,364,392 discloses a detachable balloon catheter with a neck mounted in the mouth of the balloon. The neck has a pair of grooves therein and an end of a catheter received within the neck has a pair of ridges thereon for being received in the grooves. The mating of the ridges in the grooves serves to hold the distal end of the catheter within the neck within the mouth of the balloon while the balloon is being filled with pressurized fluid. Then, a second catheter received about the first catheter having the ridges thereon is moved relative to the first catheter to urge the distal end of the second catheter against the neck thereby to detach the neck from the distal end of the first catheter.
The U.K. Pat. Publ. No. 2,019,219 discloses a self-sealing connector for use with plastic cannulas and vessel catheters wherein the connector has a disc of elastic material mounted across a passageway through the connector and the disc has a slit therein which can be forced open by fluid pressure or a rigid tube allowing fluid to pass through the disc and through the passageway in the connector.
The U.S.S.R. Inventor Certificate No. 542,523 discloses a balloon catheter wherein a balloon having an elastic contracting member around the mouth of the balloon receives a distal end of a catheter through the mouth of the balloon. Once the balloon is filled, the catheter is retracted from the balloon mouth and the elastic band closes off the mouth of the balloon to maintain the balloon inflated.
Some other patents which provide background art and which disclose various inflatable, balloon-type structures for insertion into a human body are as follows:
U.S. Pat. No. 3,978,l863 to Fettel et al; U.S. Pat. No. 3,993,080 to Loseff; U.S. Pat. No. 4,091,816 to Elam; U.S. Pat. No. 4,149,539 to Cianci; U.S. Pat. No. 4,154,243 to Patel et al; U.S. Pat. No. 4,182,328 to Bolduc et al; U.S. Pat. No. 4,188,954 to Patel et al; and U.S. Pat. No. 4,219,026 to Layton.
As will be described in greater detail hereinafter, the detachable balloon catheter of the present invention provides a miniaturized balloon catheter assembly and a method of using such balloon catheter assembly to efficiently disengage an inflated balloon from a cannula and provides a balloon assembly which is relatively easy and inexpensive to manufacture. In particular, the balloon catheter assembly and its method of use provide a simple to operate, active and stress-free mechanism for detaching with a short burst of pressure, a balloon assembly from a cannula of the balloon catheter assembly.